Their traditional symbols, the four living creatures, are taken from (anticipated in?) the prophecy of Ezekiel (1:5-21, 10:20). Of these same living creatures, borrowed by the Book of Revelation (4:6-8), St. Irenaeus says, “The lion signifies the royalty of Christ, the calf his priestly office, the man his incarnation, and the eagle the grace of the Holy Spirit.”
Matthew, Apostle and Martyr
Matthew is called the divine man, since he teaches about the human nature of Christ and since his version of the Gospel begins with Jesus’ paternal genealogy.
Mark, Martyr
Mark is called the winged lion, since he informs us of the royal dignity of Christ and since his version of the Gospel begins: “The voice of one crying in the wilderness,” suggesting the roar of the lion.
Luke, Martyr
Luke is called the winged ox, since he deals with the sacrificial aspects of Christ’s life and since his version of the Gospel begins with a temple scene.
John, Apostle
John is called the rising eagle, since his gaze pierces so far into the mysteries of heaven and since his version of the Gospel begins with a lofty prologue that is a poem of the Word become flesh.
From The Catholic Source Book.
